| 摘要 |
PURPOSE:To hold a cage of a hydraulic elevator in a safe, stationary state even if a solenoid value becomes inoperative due to blockage. CONSTITUTION:An induction motor 10 is subjected to variable speed control through the output of an inverter 23 and a hydraulic pump 9 is driven and pressure oil is fed to a cylinder 1 during up-operation of an elevator, whereas during down-operation of the elevator the motor 10 is subjected to regenerative braking by the amount of oil returning to an oil tank 13 so as to lower a cage 6. After the cage 6 stops at a floor, only a current for excitation is passed through the motor 10 to stop a speed controller 27 while the current for torque is not passed. If the blocked inoperative state of a solenoid valve 7 is detected by a solenoid valve abnormality detector 35, the current for torque is passed again to generate braking torque. |
